The invention relates to an rpm governor for a fuel injection pump of an internal combustion engine. In a known rpm governor of this type, adjustment takes place by means of an adjusting piston exposed to fuel, with the fuel flow controlled by magnetic valves. This known device is relatively expensive and, because of the elasticity of the hydraulics and the indirect electrical control through the use of hydraulics as an intermediary, it is relatively sluggish and imprecise. This is particularly true when the governor is intended to operate as an isostatic governor, with a degree of proportionality between 0 and 5%.